Interpretive Summary: Non-native ambrosia beetles are increasingly being recognized as significant pests of ornamental trees. Traps baited with ethanol lures are commonly used for monitoring ambrosia beetle flight activity in ornamental nurseries, but efforts are underway to improve trap attractiveness using olfactory and visual cues. Conophthorin is a volatile compound emitted from a variety of trees and has shown promise for increasing ambrosia beetle attraction to ethanol-baited traps. Green light emitting diodes (LEDs) also act as a visual cue to increase ambrosia beetle attraction to ethanol-baited traps. A field-based trapping experiment was conducted to determine the influence of conophthorin and green LEDs on the response of non-native ambrosia beetles. Traps were deployed with a variety of olfactory and visual treatments, including, (1) ethanol alone, (2) ethanol plus conophthorin, and (3) ethanol, conophthorin, and green LEDs. Ethanol-baited traps integrated with conophthorin and green LEDs (525 nm) were more attractive to non-native ambrosia beetles than traps baited with ethanol alone. This study indicates that ethanol-baited traps supplemented with conophthorin and green LEDs can be useful for improving the attractiveness of ambrosia beetles to ethanol-baited traps.

Technical Abstract:
Non-native ambrosia beetles are increasingly being recognized as significant pests of ornamental trees, particularly, Cnestus mutilatus (Blandford) and Xylosandrus crassiusculus (Motschulsky). Olfactory and visual cues play an important role during host location by ambrosia beetles. Ethanol-baited traps are used for monitoring flight activity of ambrosia beetles, but efforts are underway to improve trap attractiveness. The volatile compound conophthorin increases the response of some ambrosia beetles to ethanol. Green LEDs also act as a visual cue to improve trap attractiveness to ambrosia beetles. Traps were deployed to determine the attractiveness of three different treatments to bark and ambrosia beetles (Coleoptera: Curculionidae: Scolytinae), namely, traps baited with (1) ethanol alone, (2) ethanol plus conophthorin, and (3) ethanol, conophthorin, and green LEDs. Ethanol-baited traps integrated with conophthorin and green LEDs (525 nm) were more attractive to X. crassiusculus and other Scolytinae than traps baited with ethanol alone. Cnestus mutilatus capture was not affected by the addition of conophthorin, or conophthorin and green LEDs to ethanol-baited traps. This study indicates that ethanol-baited traps supplemented with conophthorin and green LEDs can be useful for improving the attractiveness of ethanol-baited traps to X. crassiusculus and other Scolytinae.